KR20230014992A - Slow release fertilizer using biodegradable SAP and manufacturing method thereof - Google Patents

Abstract

The present invention relates to: an environmentally friendly matrix-type slow release fertilizer with high economic feasibility, which is obtained by melting and mixing biodegradable SAP, biodegradable resins (rosin, wax, polycaprolactone, or mixtures of each), and the like as a matrix resin together with a urea fertilizer in an extruder, and extruding the same, and which can gradually and continuously provide fertilizer components and moisture at the same time; and a manufacturing method of the slow release fertilizer.

Description

Slow release fertilizer using biodegradable SAP and manufacturing method thereof {Slow release fertilizer using biodegradable SAP and manufacturing method thereof}

The present invention mixes biodegradable SAP, resin, and fertilizer and then extrudes them through an extruder to coat the fertilizer components with the matrix resin, which is a highly economical and environmentally friendly new type of matrix that enables continuous provision of fertilizer components and moisture. It relates to the mold conversion effect and its preparation method.

In the conventional manufacturing method of slow-acting fertilizer, a chemical method of reducing the solubility of the fertilizer component itself by chemically reacting the fertilizer component with other substances to change it into a salt that is poorly soluble in water or a non-degradable substance that is not easily decomposed by soil microorganisms, and In other words, there is a physical method of slowing down the dissolution rate of fertilizer components by coating the particle surface of the quick-acting fertilizer with a poorly soluble material that can block contact with water. Products made by chemical methods include Urea-Formaldehyde, IBDU (Isobuty lidene Diureas), and CDU, which are condensed with urea and aldehyde (U.S. Patent No. 3,227,543), but these products are manufactured by chemical synthesis. Therefore, the process is complicated and the production cost is high. Unlike the chemical method, the physical method controls the dissolution rate of the fertilizer by coating the particle surface of the quick-acting fertilizer. Therefore, there is an advantage in that the manufacturing process is simpler than the chemical method, so research and development are being actively conducted in this area. The types of coatings coated on the surface of fertilizer particles include a semi-permeable membrane (thermoplastic synthetic resin) in which the membrane is destroyed by the internal osmotic pressure generated by diffusion and the fertilizer components are eluted, and water passes through the membrane and enters the inside to dissolve the fertilizer components and enlarge the hole. There are impermeable membranes (thermosetting synthetic resins) with micropores that elute fertilizer components, and impervious membranes (biodegradable resins) that elute fertilizer components by decomposing coating materials by physicochemical or microbial activity. Materials that can be used as coating materials include synthetic resin materials and biodegradable materials, and synthetic resin materials include thermosetting resins and thermoplastic resins. Until now, coating fertilizers are those in which individual fertilizer particles are coated with a coating material, and representative examples are as follows. Osmocote (U.S. Patent No. 3,233,518), developed by Archer Daniels Midland Company in the United States, is a multi-layered coating made of a copolymer of dicyclopentadiene and glycerol ester. It is excellent, but the product is expensive and it is difficult to recover used organic solvents, so there is a high concern about environmental pollution. Sulfur-coated fertilizer (US Patent No. 3,295,950) developed by T.V.A of the United States has a low product price, but it is difficult to control the dissolution rate of the fertilizer and has a problem of acidification of the soil due to accumulated sulfur. In addition, there is a case in which silicate, which is a metal oxide, is used (Japanese Patent No. 59,137,386), but the coating material, silicate, dissolves in water and the performance of the coating film does not last long. There is a method that delays the dissolution of fertilizer components in water (Korean Patent Publication No. 88-153), but this also has the disadvantage of high manufacturing cost and the problem of residual accumulation of latex components in the soil. As described above, in the method of coating fertilizer components using synthetic separator materials, there is a problem such as soil contamination by synthetic polymer materials, so it is proposed to use biodegradable materials in addition to synthetic polymer materials. Wax insoluble in water was used as a biodegradable material (U.S. Patent No. 3,232,237). However, in the case of using wax, the wax content of the coating material is too high in order to satisfactorily suppress the dissolution rate of the fertilizer. To compensate for this, a method of mixing and melting ox and rosin and using them as a coating material (Japanese Patent Publication No. 59-35875) has been proposed. However, when rosin is used as a coating material, the coating material is dissolved in a solvent and then sprayed on fertilizer particles to form a film. In the process of forming a film, rosin is decomposed by high heat, resulting in extreme pinholes in the film. In order to eliminate the pinhole phenomenon that occurs during the process of watering the film using biodegradable materials, rosin is dissolved in an organic solvent and then a specific additive is added to use it as a coating material for granular fertilizer (Korean Patent Publication No. 93-12646). has been suggested This method allows the coating process to be performed at a low temperature, thereby suppressing the occurrence of pinholes in the rosin coating and improving the physical properties of the rosin coating to increase the effectiveness. However, in this case, due to the viscosity of the surface of the particles, the particles tend to stick together or collide with each other during storage and handling, so to compensate for this, a polymer material is added to the mixture of rosin and rosin derivatives, and then dissolved in an organic solvent to form granular A method for producing a slow release fertilizer has been proposed in which the organic polymer material is coated with a protective coating in the form of an organic solution or an emulsion solution after spraying the fertilizer (Korean Patent Publication No. 94-2203). The particles coated with this method have increased mechanical strength, which solves problems during handling and storage, but the manufacturing process is complicated and problems arise due to the use of organic solvents.

Since most of the currently used chemical fertilizers are soluble in water, the fertilizer is excessively eluted immediately after fertilization, and the amount of loss of the fertilized fertilizer is large, resulting in a decrease in the utilization rate of fertilizer. There are problems such as waste of labor due to frequent fertilization. Therefore, there is an urgent need to develop a slow-acting fertilizer that can reduce the loss of fertilized fertilizer, reduce labor force due to frequent fertilization, and continuously supply fertilizer components throughout the entire growth period of crops. In addition, there is a difficulty in supplying water frequently due to poor sustainability in providing moisture, so the development of a slow-acting fertilizer using biodegradable SAP that can solve the problem of supplying water and fertilizer at the same time and minimize soil contamination is particularly important for field crops. It is more urgently needed.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a matrix-type slow release fertilizer and a manufacturing method thereof produced by a completely different coating method from existing coated fertilizers. In addition, it has the characteristics of being manufactured so that water can be provided at the same time by mixing biodegradable SAP. Matrix type slow release fertilizer according to the present invention for achieving the above object is 5-80% by weight of SAP component granules and 5-80% by weight of resin component granules It is characterized in that it is formed so that 20-95% by weight of fertilizer particles are dispersed and present. In addition, the method for producing a matrix-type slow-release fertilizer according to the present invention includes 5-80% by weight of SAP component, 5-80% by weight of resin component, 20-95% by weight of fertilizer component, 0-20% by weight of surface compatibilizer if necessary, desiccant It is characterized in that the mixture composed of 0-20% by weight is melt-mixed in an extruder and then compressed to coat the fertilizer component with a matrix resin. Since the matrix-type slow-release fertilizer produced by the manufacturing method as described above is a state in which fertilizer particles are dispersed in a matrix-type three-dimensional phase composed of SAP and resin components, it is easy to control the dissolution rate of fertilizer components in water by adjusting the weight ratio of the resin. In addition, since a large amount of fertilizer components can be coated with a small amount of coating material (resin), environmental pollution can be minimized, and since organic solvents are not used, solvent recovery problems do not occur, and the process is simple. there is

The matrix-type slow-release fertilizer prepared by the manufacturing method of the present invention uses biodegradable SAP and resin and solves the problem of environmental and soil contamination by not using specific additives or organic solvents at all. In addition, since biodegradable resins, such as rosin, wax, and polycaprolactone, which have similar melting points, are all available, raw materials used in conventional spray coating can be used, so the range of raw material selection is wide, and they can be appropriated according to the application in the form of pulverized or as is. It is mixed with fertilizer by weight %, mixed in a super mix, kneader or banbari, and then put into an extruder, which simplifies the manufacturing process because no pretreatment process is required, thereby reducing manufacturing costs, and thus mass production is possible. It is possible, and phosphate, potassium, and organic fertilizers as well as urea fertilizers can be used to manufacture slow-acting fertilizers for various purposes. In addition, when mixing biodegradable SAP, biodegradable resin (rosin, wax polycaprolactone, or each mixture) and fertilizer (urea fertilizer, phosphate fertilizer, potassium fertilizer, organic fertilizer, or compound fertilizer), desiccant (calcium chloride, calcium oxide) Fertilizer coated through an extruder after adding and mixing the fertilizer reduces the occurrence of pores generated by water evaporation during melting and mixing, and the coating layer becomes hard to prevent water penetration, so in the case of hygroscopic urea fertilizer particles, better efficiency will appear. When the surface compatibilizer is added, it is possible to obtain high-strength compressed pellets by increasing the adhesive force between the hydrophilicity of the fertilizer particles and the hydrophobicity of the biodegradable resin, so it is easy to control the elution amount after transportation, storage and fertilization by increasing the strength of the coated fertilizer. . In addition, compared to pellets obtained by passing through a single-screw extruder, pellets passed through a twin-screw extruder or extruded through a twin-screw extruder and then extruded through a single-screw extruder have increased mechanical strength and effectiveness, and are applied to field crops that require a long period of fertilizer elution. this is possible

Figure 1 (a) is a cross-sectional view of the mattress-type slow release fertilizer coated by the manufacturing method of the present invention
Figure 1 (b) is a cross-sectional view of the fertilizer coated by the conventional spray coating method

The present invention will be described in more detail with examples as follows.

These examples show a part of the present invention, and the scope of the present invention is not limited by these examples.

[Example 1]

This example shows the characteristics of the manufacturing process. 2.5 kg of commercially available particulate urea fertilizer, 2.5 kg of SAP, 4 kg of pulverized gum rosin, 1 kg of wax, screw rotation speed of 100 rpm, temperature of 60-110 ° C. It is put into the operated single-screw extruder. The coated fertilizer passed through the extruder die was cut into a certain size and the effectivity test was conducted, and the results were shown in Table 1 below. The dissolution test obtained the result by measuring the amount of fertilizer eluted from the 30 ℃ thermostat.

1 day 10 days 20 days 30 days 40 days Dissolution rate (%) 1.0 5 13 25 43

[Example 2]

3.5 kg of commercially available granular urea fertilizer, 3.5 kg of SAP, and 3 kg of pulverized gum rosin were added to the supermix and mixed. The mixed material is put into a twin-screw extruder, where the temperature in the extruder is maintained at 80-120° C. and the rotational speed of the screw is 200 rpm. As a result of conducting the efficacy test in the same manner as in Example 1, the results were shown in Table 2 below.

1 day 10 days 20 days 30 days 40 days Dissolution rate (%) 3.0 10 20 35 45

[Example 3]

3.5 kg of commercially available granular urea fertilizer, 3.5 kg of SAP, and 2.5 kg of pulverized gum rosin were mixed with 0.5 kg of stearic acid in a supermix. The mixed material is put into a twin-screw extruder, where the temperature in the extruder is maintained at 80-120° C. and the rotational speed of the screw is 200 rpm. The mixture passing through the die of the twin-screw extruder is put into the single-screw extruder again. At this time, the temperature in the single-screw extruder is operated at 60-120 ° C., and the rotational speed of the screw is maintained at 150 rpm. As a result of conducting the efficacy test in the same manner as in Example 1, the results are shown in Table 3 below.

1 day 10 days 20 days 30 days 40 days Dissolution rate (%) 0.1 3 12 25 40

[Example 4]

Put 4 kg of SAP, 1.7 kg of gum rosin, and 0.3 kg of stearic acid into 4 kg of commercially available granular urea fertilizer, put them in a preheated banbari at 120 ° C, mix for 5 minutes, and then test the elution with mixed coating in the same manner as in Example 1. The result was shown in Table 4 below.

1 day 10 days 20 days 30 days 40 days Dissolution rate (%) 0.5 5 15 30 50

Claims (9)

5-80% by weight of biodegradable SAP component granules, 5-80kg% by weight of resin component granules, 20-95% by weight of fertilizer particles are dispersed and present matrix-type slow release fertilizer. The matrix-type slow-acting fertilizer according to claim 1, wherein the resin component can be softened at 50-150 ° C and is used alone or in combination with synthetic resins such as thermoplastic resins or thermosetting resins or biodegradable resins. [Claim 3] The matrix slow release fertilizer according to claim 2, wherein the biodegradable resin is selected from gum rosin, wood rosin, tall oil rosin, wax, and polycaprolactone. The matrix type according to claim 1, wherein the fertilizer component is selected from urea fertilizer, phosphate fertilizer, potash fertilizer, organic fertilizer, or compound fertilizer, and is used as it is or pulverized to 5-200 μm. slow release fertilizer. The matrix-type slow-release fertilizer according to claim 1, further comprising 0-20% of a surface agent and 0-20% by weight of a desiccant in addition to the SAP component, the resin component and the fertilizer component. [6] The matrix-type slow release fertilizer according to claim 5, wherein the surface compatibilizer is selected from fatty acids such as oleic acid, stearic acid, and palmitic acid. The matrix-type slow-release fertilizer according to claim 5, wherein the desiccant is selected from calcium chloride and calcium oxide. A mixture composed of 5-8% by weight of resin component, 20-95% by weight of fertilizer component, 0-20% by weight of surface compatibilizer, and 0-20% by weight of desiccant is melt-mixed in an extruder and then extruded to extrude the fertilizer component. A method for producing a matrix-type slow release fertilizer, characterized in that for coating with a matrix resin. The method of claim 8, wherein the extrusion method is through a single-screw extruder, a method through a twin-screw extruder, a method through a single-screw or twin-screw extruder after passing through a twin-screw extruder, a single-screw or twin-screw extruder after mixing in a kneader, banbari, or supermix Method for producing a slow-acting fertilizer, characterized in that selected from the method through.

Images